Thai Pyrogen deaths a grim reminder
The tragic deaths of eight people following the accidental triggering of a Pyrogen extinguishing system in a Thai bank in March 2016 should not happen in Australia as long as the necessary standards are used.
Pyrogen systems have been sold and installed in Australia for more than 20 years. Pyrogen is a specific brand of a type of product, known as a ‘condensed aerosol fire extinguishing agent’. This article provides guidance in relation to the Australian Standard for such systems and recommendations to ensure locally installed systems incorporate the safety features required by AS 4487 to minimise the possibility of a similar incident occurring.
While the incident in Thailand related to a specific brand of condensed aerosol, it should be noted that different brands have different chemistries and as a result different toxicology. At least one condensed aerosol product has a sufficiently safe toxicological profile to be listed with the US Environmental Protection Agency Significant New Alternatives Policy (US EPA SNAP) and approved for use in occupied spaces.
Enquiries about the specific approvals and toxicological information on individual brands of condensed aerosols should be directed to the relevant manufacturer or supplier.
Australian standard requirements
Australian Standard AS 4487 Condensed aerosol fire extinguishing systems – requirements for system design, installation and commissioning and test methods for components provides guidelines for these types of systems.
It details the potential safety hazards associated with condensed aerosols and specifies safety precautions and features to be incorporated in such systems to minimise the risk of exposing people to a discharge of condensed aerosol.
These are some of the safety hazards and precautions detailed in AS 4487:
- Potential hazards of aerosol extinguishing systems include noise, reduced visibility, high temperature, turbulence, potential toxicity and skin or eye irritation to people in the protected space and other areas where the aerosol may migrate.
- Determination for use of an agent in spaces that are normally occupied or normally unoccupied shall be based on an evaluation of the adverse effects(s) caused due to accidental exposure to the aerosol
- In any proposed use of aerosol where people may enter the protected enclosure or be close to the protected risk, suitable safeguards such as personnel training, warning signs, pre-discharge alarms and system isolate switches shall be provided. Means of ventilation after fire shall be readily available
- Aerosol generators shall be installed in such a manner that they will not potentially cause injury to personnel. Condensed aerosol shall not directly impinge on areas where personnel may be located.
In addition to the above warnings, AS 4487 specifies that the following safety features be incorporated into condensed aerosol systems:
- Automatic/manual switch, to allow the system to be placed in manual mode when the protected enclosure is occupied.
- System isolate switch to prevent discharge of the system during maintenance activities.
- Exit routes and emergency lighting and adequate direction signs to minimise travel distances from areas that may be occupied.
- Outward-swinging, self-closing doors that can be opened from the inside, including when locked from the outside.
- Continuous visual and audible alarms at entrances and designated exits inside the protected area and a continuous visual alarm outside the protected area, which operate until the protected area has been made safe.
- Appropriate warning and instruction signs. Warning notices must be provided at all entrances to the protected enclosure.
- Means for prompt natural or forced-draft ventilation after discharge.
If you have a Pyrogen system installed in your facility or you service a facility with such a system installed, the following is strongly recommended.
- An audit of the system be conducted to ascertain its compliance to the requirements of the current edition of AS 4487 (land-based systems).
- The system is upgraded to incorporate the important safety features specified in AS 4487 or replaced with an alternative fire extinguishing system.
Note: While it is not a specific requirement of AS 4487, it is recommended that dual stage detection and control systems be installed (where appropriate) in conjunction with condensed aerosol extinguishing systems so as to minimise the possibility of accidental operation.
- An audit of the system be conducted to ascertain its compliance to the requirements of the current edition of the National Standard for Commercial Vessels (NSCV).
- The system is upgraded to incorporate the important safety features specified in the NSCV or replaced with an alternative fire extinguishing system.
Note: When servicing any condensed aerosol system, it is essential that the aerosol generators are electrically disconnected before undertaking any service activities that could cause an unintended discharge of the system.
For more information, go to www.fpaa.com.au